Ah, I'm finding this thread very heartwarming - I didn't think there'd be so much love for bats amongst MNers! 
Glad it turned out to be non-creepy-crawly (though I don't like the look of the stain on the wallpaper, OP).
Just wanted to add a few bat facts...
Looks like a bat. Legally you shouldn't touch it because they are protected species that you have to hold a special licence to handle.
This is technically true, but there are exceptions to the law. It's illegal to disturb a roost or interfere with a bat, but it's not illegal to handle a bat that needs help. Hanging on a wall in a cupboard would definitely fall into that category, as would any bat that was trapped, injured or in distress.
It's really important that, if you're going to handle a bat that needs help, you make sure you're wearing gloves, or use a cloth to pick it up. Bats can carry a rabies-family virus, and although it's very, very rare, it's not worth taking any risks. The live virus (EBLV) has only ever been found in Daubenton's bats in this country, and antibodies indicating past infection have been found in a couple of Natterers and a Serotine. The vast majority of bats that the public encounter, or who end up in houses, are Pipistrelles.
If you find a bat that needs help, pick it up using gloves, put it in a shoebox with a soft cloth and a milk bottle top of water, and ring the BCT. They'll put you in touch with a carer who'll come and pick it up. 